Despite 28 years of effort at optimization, JavaScript is outperformed by WebAssembly. There's not much coming back from that:
https://jordaneldredge.com/blog/speeding-up-winamps-music-vi...
https://www.amazon.science/blog/how-prime-video-updates-its-...
It doesn’t matter. What matters is what people put in their web pages.
With WebAssembly every language runs in the browser and runs better.
A lot of things that bring a lot of value to a lot of people are still much, much faster to build via the JS / TS ecosystem.
It absolutely makes sense that calculation-heavy workloads will be ported to WASM, but there's a lot more to building an app.
Like what? Visual UI designers? WebAssembly's got you covered: https://platform.uno/blog/uno-platform-studio-featuring-hot-...
Running Visual Basic in a C# application compiled to WebAssembly? Sure, why not: https://bandysc.github.io/AvaloniaVisualBasic6/